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Effects of silicon in plants with particular reference to horticultural crops - Review article
95-105.Views:320Silicon (Si) has long been considered as non-essential element for plant’s growth and production. Numerous efforts are being made for the discovery of its beneficial effects with large scale studies laying foundation for new findings and hypotheses. Therefore, Si has been suggested to be a quasi-essential element due to its positive effects against biotic and abiotic stresses alike. Though Si is the second most abundant element in the soil profile, its availability to plants is limited to the form of monosilicic acid only. Besides, plants’ ability to take-up Si and use it in their physiological processes also depends on the available transporters associated with it. Thus, the present review covers uptake and transport of silicon in plants as well as Si mediated physiological processes, including mechanisms underlying induced tolerance against biotic and abiotic stresses with a particular emphasis on horticultural species.
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Cracking susceptibility of sour cherry (Prunus cerasus L.) in Hungary and relation to calcium application
109-118.Views:306The rain induced fruit cracking is a big, serious problem especially for sour cherry growers but in some year sour cherry growers had also problem with fruit cracking caused by too much rainfall in the harvesting season. The cracked sour cherry fruits can be easily infected by different diseases like Monillinia sp. Cracked and infected fruits can not be transported for long distance and using for preservation because they lost their market value by the pour fruit quality. There are two possibilities to protect fruits against the rain induced fruit cracking. The most effective protection technique is the plastic rain cover over the tree rows. The installation of these equipments is too expensive for the growers. That is the reason why researchers tried to find other less expensive and sufficiently effective ways like sprayings different mineral salts, hormone and other type chemicals against the rain induced fruit cracking. Several calcium formulas calcium chloride (CaC12), calcium hydroxide (Ca (OH),) and calcium nitrate (Ca(NO3)2) can be sprayed in appropriate solution concentration.
The aim of our trial is to determinate the fruit cracking susceptibility of wide grown Hungarian sour cherry varieties and find the most effective calcium formula and its concentration for spraying in orchards to prevent the fruit cracking. In the first trial year (2006) cracking index of tested sour cherry varieties were determined under field and laboratory conditions. Under field conditions were not found differences between cracking tendency of tested cultivars. After results of immersing fruits in distillated water for 24 hours tested sour cherry varieties were divided to three groups by the susceptibility to rain induced fruit cracking: very susceptible (`Maliga emléke', 'Piramis', 'Érdi jubileum', 'Erdi nagygyümölcsű’ and 'Meteor korai'); susceptible ‘Érdi bőtermő, Tandy 279' and Cigány 59.; moderately susceptible/tolerant ("T" and "R" clones). In the second trial year (2007) calcium chloride (CaCl2) and calcium nitrate (Ca(NO3)2) were sprayed in 0,35m/m%; 0,5m/m% and 1,0m/m% solution concentration. One more commercial product "Damisol-Kalcium" was also applied in the advised 1,0m/m% concentration. Like in the trial year before (2006) under field conditions we did not kept differences between the cracking susceptibility of varieties and calcium treatments. As the result of laboratory testing (immersing calcium treated fruits in distillated water) we kept that calcium chloride (CaCl2) seems the most effective against the fruit cracking in 0,5m/in% solution concentration. The other calcium formulas also decreased the cracking ratio but in less scale.
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Perspectives and tasks in horticultural production
11-22.Views:201The work summarizes the prospective conceptions of all the five horticultural branches. These branches (vegetable, fruit, grape and wine, herb and ornamental plant production) with the production of propagating material together amount to round 30-35% of the total value of the entire plant production. The performance of horticultural branches declined significantly because of privatisation and lack of capital. The accession to the EU urges the development of modernization and competitiveness, therefore the state subsidies are indispensable.
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Concentration of ‘Oblachinska’ sour cherry juice using osmotic distillation
31-34.Views:253Sour cherry is one of the most famous and characteristic Hungarian fruit what is also commonly used in food production as a colour additive. The sour cherry cultivar, ‘Oblachinska’ was shown to be a rich source of antioxidant compounds, including mainly anthocyanins. Valuable compounds in fruit juice – vitamins, polyphyenols etc. –are heat-sensitive molecules, which should be taken into account during the process of concentration to prevent degradation. Osmotic distillation seems a suitable option to product high quality sour cherry juice because this process does not require high temperature or pressure. Raw juice with approximately 15°Brix was used for the experiment and tried to concentrate up to 60° Brix where the water activity low enough to inhibit the microbiological deterioration. Before and after the process, TPC (total phenolic compounds) and FRAP (ferric reducing antioxidant power) was measured using spectrophotometric methods to determine the effect of the osmotic distillation. Our results point out that osmotic distillation is a promising method to concentrate sour cherry juice and prevent the loss of valuable compounds.
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Reactions of different plant organs of pear cultivars to Erwinia amylovora infection
17-21.Views:137Research project has been initiated in 1999 with the aim of evaluating the degree of susceptibility/resistance of pear cultivars grown in Hungary to fire blight disease caused by Erwinia amylovora. The recently selected promising cultivars were also examined. Inoculation experiments were conducted in controlled greenhouse conditions because of quarantine regulations in Hungary. Following the disease process, development of symptoms of plant organs (shoots, flower parts, fruits) was observed. Suspension of two E. amylovora strains (Ea 21, Ea 23) isolated from pear was used in a mixture (5x108 cells x m1-1) for the inoculation. Twenty-six pear cultivars were examined and grouped into four categories: low susceptibility, moderately susceptible, susceptible and very susceptible. Most of the cultivars were susceptible or very susceptible while some promising 'Eldorado', 'Harrow Delight' and `Hosui' showed low susceptibility.